There have been slot machines in arcades, pubs and clubs for many years, starting with the three reel fruit machines and then gradually becoming more sophisticated as time went on. It is fair to say that most of us have probably played these machines at some time in our lives, and even those of us who enjoyed casino gambling at a real casino will have seen a few slot machines sited somewhere in the casino where space permitted. Nowadays of course the introduction of casino gambling online has resulted in a massive change to the concept of gambling on slots. The online casinos all offer a huge range of gambling games for us to enjoy, including many more of the traditional gambling games such as craps, baccarat and backgammon, but the vast majority of the new gambling games are slots games. Not only is the choice of slots gambling games quite staggering, but they have developed far beyond anything that was available before online casino gambling became available. It is generally considered to be the slots gambling games which define the difference between one online casino gambling site and another and they represent the biggest marketing tool for almost every online casino gambling site operator. Usually found under the heading ‘other games’ the slots are the reason why the online casino software companies have become so important because it is the software designers who have led the development of the modern online slots games. Fans of gambling on slots can choose from a huge variety of themes, ranging from films and cartoons to popular television programmes, and even a range of sporting themes for sports fans. There are now slots gambling games with up to five reels and any number of winning lines on each spin. There appears to be no end to the imagination of the slots designers and new games are being introduced all the time.